Fluid pump



ume 29, 1948.. L.. E. GoDFRxAux 2,444,159

Louis' EGoqfrauf AT TORNEY N INVENTOR. s

' BY V June 29,1948, L E GODFRIAUX y 2,444,159

Patented June 29, 1948 oFFlcE FLUID PUMP Louis E. Godfriaux, Madison, Wis., assigner to Gisholt Machine Company, Madison, Wis., a corporation of Wisconsin Application September 20, 1944, Serial No. 554,884 (Cl. a-38) A 13 Claims. l

'This invention relates to a iluid pump where- I in a plurality of adjacent pistons are driven by adjustable eccentric cam members on a rotating shaft. y

In such pumps the stroke of the pistons determines the volume of iluid pumped and is adjusted by varying the eccentricity of the cam members on the shaft. Heretofore this adjustment has been madeby a longitudinally movable cam rod extending axially within the shaft and having cam surfaces which positively engage radially .movable members which support the cylindrical cam members in eccentric position. Operation of such a cam rod during pumping operations wherein one or more pistons would be in the working stroke cycle was dicult and in many cases exceeded the available force.

The principal object of Ithe present invention is to provide a more readily operable adjustment for the eccentric cam members so that the stroke of the pistons can be adjusted with very light pressures upon the adjusting rod.

Another object is to provide a self-locking cam adjustment for s'uch a. pumpso that the adjusting members are not stressed to a point of altering the adjustment by reason of the internal uid pressures in the cylinders.

Another object is to provide more eillcient adjusting mechanism whereby accurate adjustments of the stroke of the pistons can be made readily and .in either small or large increments during operation of the pump and throughout the range of adjustment provided.

Another object is to eliminate the opposition to adjustment resulting from the forces involved during the working stroke of the several pistons.

A further object is to provide a more eillcient liquid pump', and one in which the volume of liquid being pumped can be accurately controlled at all times.

A further object is to prevent loss of volume and pressure by reason of the entrapment of gases in the cylinders of a liquid pump.

In carrying out the invention the cam surfaces for actuating the radially movable members controlling the eccentrlcs lare disposed on separate independently movable members instead of The cylinders have a stationary central plug member extending into each of the pistons to provide long narrow passages for the liquid from the inlet port to the outlet port for flushing the same.

A pump embodying the invention is illustrated in the accompanying drawings in which:

Figure l is a longitudinal section taken onthe axis of the pump shaft in the plane of the center lines of the several pistons and cylinders;

Fig. 2 is a transverse section taken on line 2 2 of Fig. 1 through the center line of the left hand cylinder;

Fig. 3 is a-transverse section similar to Fig. 2

taken on line 3-3 of Fig. 1 through the center line of the center cylinder; and Fig. 4 is a transverse section similar to Fig. 2 taken on line 4 4 of Fig. 1 throughthe center line of the right hand cylinder. y

The fluid pump comprises a pump shaft I rotatablyl mounted in suitable end bearings 2 in a pump housing 3, which provides a plurality of pump cylinders 4 disposed side by side with their parallel center lines spaced along the shaft and radial toit.

A cylinder head block 5 is secured to housing 3 and closes the outer ends of cylinders 4. The block 5 is provided with two ports 6 and 1 for each cylinder, port 6 entering the cylinder near its outer Wall and port 1 being disposed on the center line of the cylinder. Port 6 constitutes the inlet port for admitting fluid to the cylinder and port 'l constitutes the discharge port for the cylinder.v

The control of the flow of fluid to and from each cylinder may be provided by the ball check valves 8 and 9 disposed in a valve housing I0 secured in head 5. The valve 8 admits Huid to the cylinder but checks its escape through inlet port being fixed upon anactuating rod, and the individual members are biased by springs therebetween to adjusted longitudinal positions inside the shaft. The exact position of the individual members is determined by a rod extending axially of the members and controlling the movement of the several members under the inuence of the springs.

6. Valve Ii) allows discharge of uid through port 'l but checks its return to the'cylinder.

The cover plate II secured to head 5 provides the inlet passage I2 and discharge passage I3 with branch passages for each cylinder, connecting passages I2 and I3 to the respective valves in blocks I0.

The cylinders 4 contain individual pistons I4 adapted to reciprocate therein. The pistons I4 are in the shape of long hollow tubular members fitting the walls of the cylinders 4 and closed at the upper end. A coil spring I5 extends inside each piston I4 between its closed end and the bottom of the cylinder to bias the piston upwardly at all times.

j Each cylinder contains a central tubular plug I6 secured in port 1 in head 5 and extending upwardly inside the piston I4 nearly to its closed end when the piston is at the bottom of its working stroke. The objective of the plugs I6 is to compel the fluid to follow a definite path in its pas- 'sage into and out of the cylinder 4 with the passage confined to rather narrow dimensions so that no pockets of air or gas will develop in the cylinder tending to destroy the effective pressure and volume of discharge. By having plug I6 extend to the upper end of the piston the rapid flow of liquid over the upper edge of the plug as the piston moves downwardly in the working stroke clears the piston of any air pockets.

The pistons I4 are driven downwardly by means of cam rings I1 mounted on the rotating power shaft and engaging corresponding rollers I8 on the top of the respective pistons. The rollers |8 are mounted on suitable bearings and have their axes parallel to shaft I. A loose key I9 inserted through the wall of each cylinder 4 extends into a longitudinal slot 20 in the wall of the corresponding piston I4 tovl keep the piston from turning, so that roller I8 will always be retained parallel to the shaft I. A

The piston rollers I8 are kept in engagement with the outer surface of the corresponding rings I1 at all times. During the working stroke of each piston I4 the ring |1 is forcing the roller I8 and its piston downwardly in cylinder 4. When the ring I1 passes dead center and its lower surface starts upwardly the spring I together with the pressure uid coming into the cylinder through valve 8 and port li raises the` piston so that roller I8 follows the ring I1 in its upward movement. For this purpose the incoming fluid should be under an initial pressure so that spring I5 may be relatively light. In this way the spring I5 supports the weight of the piston but does not become a substantial factor in opposing the movement of the piston in its working stroke in which the fluid inside the cylinder is compressed and is discharged through tube I6 and valve 9.

For the purpose of varying the eccentricity of rings I1 on shaft I, and the resulting length of stroke of the pistons I4, each ring I1 is mounted on a pair of segmental supporting blocksf2| slideccentricity of ring 1 from zero eccentricity when centered relatively to shaft I to maximum eccentricity when moved to one side of the shaft I.

The longitudinal position of the cam members 24 is controlled between inner and outer limits by a push button 25 in the outer end of shaft I. A key 26 extends through the wall of the shaft I and into a slot 21 in push button 25 for compelling its rotation with the shaft and limiting the outward movement of the push button axially of the shaft.

The push button presses inwardly against the left hand member v24 by means of a coil spring 28 disposed in a recess 29 in the adjacent end of the member 24, and the push button has its end reduced in diameter to provldea projection 30 which is adapted to enter recess 29 to compress the spring 28 when making an adjustment.

Each member 24 has an axially movable pin 3| of the same length as the member, the pin having a head 32 on its inner end for engaging the end of the member 24. The heads 32 on the left hand pin and the central pin are adapted to enter recesses 29 in the outer ends of the corresponding next adjacent members 24 and are biased outwardly therefrom by .the coil springs 28 hand or inner pin 3| normally engages the head able laterally ofI shaft I and disposed in diametrically opposed parallel transverseslots in the shaft. A pair of substantially radially disposed pins 22 extend in opposite directions through the walls of the hollow shaft I and project into engagement with the opposite surfaces of the inner wall of ring I1. By moving the pins 22 in unison diametrically of the shaft I the eccentricity of ring I1 on the shaft can be varied to any desired adjustment.

The pins 22 for each ring I1 have their inner ends supportedI in individual cam slots 23 in corresponding cam members 24 longitudinally movable in shaft I and rotating therewith. The bottoms of slots 23 are parallel and slant relative to the axis of shaft I so that longitudinal movement of member 24 forces one of the pins 22 outwardly while enabling the other pin to move inwardly a corresponding amount. The bottoms of the corresponding slots 23 of the several members 24 slant in the same general direction. The longitudinal position of each member 24 in shaft I and relative' to its pins 22 determines the eccentricity of the corresponding ring I1, there being one cam member 24 for each ring.

One of the pins 22 of each pair is longer than the other to provide for .an adjustment of the 32 of the central pin.

'Ihe head 32 of the right hand pin 3| thrusts against the outer race of thrust bearing 33, the other part of the bearing being relatively stationary with respect to the rotation of shaft I and constituting an axially movable cylindrical member 34 disposed in an extension 35 of housing 3 and biased outwardly against the pins 3| and lgitton 25 by means of a coil spring 36 in housing Normally the spring 36 is sufficiently strong to retain the several pins 3| and their respective heads 32 and the button 25 in contact with each other in their aligned arrangement axially of shaft I.

In any normal position of adjustment the springs 28 are of sufcient strength to hold the corresponding cam members 24 pressed as far to the right as the adjacent heads 32 will allow. The slant of the bottoms of. cam slots 23 should be suiciently small so that under the pumping pressures involved the members will be self-locked in position and there will be no movement of the relaiective members toward the left against springs Should it be desired to move the cam members 24 to the left for reducing the stroke of the pistons from that illustrated in the drawing, the button 25 is released to move outwardly under the influence of the left hand spring 28 to the new position of adjustment. In the event the left hand piston I4 is in that portion of its cycle where its pressure against ring I1 and `pins 22 opposes movement of the corresponding member 24 to the left, button 25 will move left tov the new position without being immediately followed by the adjacent member 24. I

As soon as the left hand piston I4 reachesa point in its cycle where its pressure against ring I1 and the pins 22 does not oppose, or in fact encourages, movement of the corresponding cam member 24 to the left, suchmovernent will occur under the influence of the corresponding central where pin 3| engages the projection 30 on button 25. At this point the central spring 28 becomes lengthened and weaker than the right spring 28 thereby allowing the central cam member 24 to click over tothe left until its pin 3| engages the head 32 of the adjacent pin, as soon as the central piston I4 and corresponding ring l1 and pins 2v2 have reached that point in their cycle where such movement is encouraged.

This is followed by the right hand member 24 rclicking to the left to its new position where the ring l1 and pins 22 are in a favorable position of their cycle. The spring biases all of the pins 3l to the left as far as the button 25 permits and secures them in their new positions. The springs 28 bias the respective members 24 to the right against the heads 32 of the corresponding pins 3|` and thereby secures the members in their adjusted position.

Should it be desired to move the cam members 24 to the right in adjusting the stroke of the pistons, a light pressure is applied to button 25 to move it inwardly of the shaft a distance corresponding to that required for the desired adjustment of cam,members 24.` Movement of button 25 inwardly immediately moves the successive pins 3| and pin 34 to the right against the spring 36. The movement of button 25 to the right docs not necessarily result in instantaneous movement of the members 24, however. The members 24 will click to the right in succession as their corresponding pistons, rings and radial pins reach a favorable point in their cycle of movement to `encourage the movement of the respective members 24. In this instance the adjustment of members 24 may be in any order, depending upon which piston reaches its favorable position first after button 25 is pushed inwardly.

The adjustment of the pump is only possible during rotation of the shaft I and it occurs within less than a single revolution of the shaft. In practice the pump will be under constant control from a lever arm 3l pressing against button 25 with a force approximating that of spring 36 plus the additional force offered by springs 28.

Various embodiments of the invention may be ,employed within the scope of the accompanying claims.

I claim:

1. In a pump of the class described, a plurality of cylinders having pump pistons therein, a rotary pump shaft having individual cam members thereon for driving said pistons, means movable in a direction substantially radial to the shaft for adjusting said members and securing the same in an adjusted position of eccentricity to vary i and determine the stroke of the pistons, separate cam means movablelongitudinally of the shaft for radially adjusting each of said first named means, and a common actuator means extending axially through said cam means for operating th same in correlation.

2. In a pump of the class described, a plurality of cylinders having pump pistons therein, a rotary pump shaft having individual cam members thereon for driving' said pistons, means movable in a direction substantially radial to the shaft for adjusting said cam members and securing the same in an adjusted positionr of eccentricity to vary and determine the stroke of the pistons. separate cam means movable longitudinally of the shaft for radially adjusting each of said first .fil

named means. and means for separately actuating said separate cam means from a single operating movement and in correlation to each other.

3. In a pump of the class described, a plurality of cylinders having pump pistons therein, a rotary pump shaft having cam members thereon for driving said pistons, means movable in a direction substantially radial to the shaft for adjusting said cam members and securing the same in an adjusted position of eccentricity to vary and determine the stroke of the pistons, separate cam means movable substantially axially of the shaft for radially adjusting each` of said first named means, means to move said separate cam means to adjust the position thereof, and delay action means' for separately adjusting said cam means after operation of said last named means and at a time `when the movement of the correspond-ing pistons facilitates th adjustment.

4. In a pump of the class described, a plurality of cylinders having pump pistons therein, a rotary pump shaft having cam members thereon for driving said pistons, means movable in a direction substantially radial to the shaft for adjusting `said cam members and securing the same in an adjusted position of eccentricity relative to the shaft to vary and determine the stroke of the pistons, separate cam means movable substantially axially of the shaft for radially adjust- .ing each of said rst named means, means for individually limiting the movement of said separate cam means inone direction, means to bias said cam means against the corresponding limits,

and means for adjusting the axial position of said 5. In a variable stroke piston pump of the class described, a pump cylinder. a piston disposed to reciprocate therein, a rotary pump shaft having a cam member thereon f or driving said piston, substantially radially movable means for adjusting said cam member and securing the same in an adjusted position of eccentricity relative to the shaft to vary and determine the stroke of the piston, cam mea-ns movable substantially axially of the shaft for radially adjusting said first named means, and operating means to adjust the longitudinal position of said cam means, including a delayed action means for effecting said adjustment at a time when'the movement of said piston facilitates the adjustment following the operation of said operating means.

6. In a variable stroke piston pump of the class described, a pump cylinder, a piston disposed to reciprocate therein, a rotary pump shaft having a cam surface thereon with its axis extending transversely to the cylinder, a, transverse roller having its axis parallel to the axis of said shaft.

said roller being attached to said piston and surface as the latter revolves with said shaft, said cylinder having ports for admitting and discharging fluid being pumped.

7. In a variable stroke piston pump of the class described, a pump cylinder, a piston disposed to reciprocate therein, a rotary pump shaft having a cam surface thereon with its axis extending transversely to' the cylinder, a transverse roller having its axis parallel to the axis of said shaft, said roller being attached to Vsaid piston and adapted to engage saidcam surface to drive the piston. a spring biasing said piston outwardly to maintain the roller in contact with said cam surface as the latter revolves with said shaft, said cylinder having ports for admitting and discharging iiuid being pumped, and means for preventing rotation of said piston on its axis.

8. In a variable stroke piston pump of the class described. a pump cylinder, a piston disposed lto reciprocate'therein, a rotary pump Shaft having a cam surfacethereon with its axis extending transversely to the cylinder, a transverse roller having-its axis parallel to the axis of said shaft, said roller being attached to said piston and yadapted to engage said cam surface to drive the r piston, a spring in said cylinder biasing said pistonv outwardly to main-tain the roller in/contact withsaid cam surface as the latter rotates with said shaft, an inlet port for pressure fluid to said cylinder, and an outlet port for pumped fluid from said cylinder.

9. In a variable stroke piston pump of the class described, ai pump cylinder, a piston disposed to reciprocate therein, a rotary pump shaft having a cam surface thereon with its axis extending transversely to the cylinder, a transverse roller having its axis parallel to the axis of said shaft, said roller being attached to said piston and adapted to engage said cam surface to drive the piston, a spring in said cylinder biasing said piston outwardly to maintain the roller in contact with said cam .surface as the latter rotates with said shaft, an inlet port for pressure iiuid to said cylinder, an outlet port for pumped fluid from said cylinder, and means'in said cylinder for confining the passage of fluid therethrough to narrow limits to avoid entrapment of air pockets therein.

10. In a variable stroke piston pump of the class described, a pump c "`nder, a piston disposed to reciprocate therein and having an outer' wall extending for substantially the length of said cylinder with allowance for a short stroke of the piston, a rotary shaft having a cam surface for operating said piston, and a cam follower attached to the piston and engaging said cam surface to transmit reciprocating movement to said piston as the ,cam rotates, said length of bearing f described, a pump cylinder of substantial length having a closed end, a piston disposed to reciprocate therein and having a tubular outer Wall extending for substantially the length of said cylinder with allowance for a short stroke of the piston, an inlet and an outlet port for said cylinder and disposed at the closed end thereof, and means separating saidports and extending into the hollow piston to conne the passage of liquid into and out of the cylinder'to a narrow passage and effect flushing of the cylinder in operation to thereby prevent entrapment of gas pockets there- 1n.

12. In a variable stroke piston pump of the class described, a plurality of cylinders having pump pistons therein, aA rotary pump shaft having cam members thereon disposed to drive said plstons as the shaft rotates, individual means carried by the shaft and rotating therewith for adjusting the respective cam members and securing the same in an adjusted position of eccentricity relativeto the shaft to vary and determine the stroke of the pistons, a common actuating means for operating said individual means, and delayed action means for delaying the individual adjustment of any cam member whose piston is moving in a direction opposing such -adjustment at the time of the operation of said common actuating means.

13. In a variable stroke piston pump of the class described, a pump cylinder disposed with its longitudinal axis vertical, a piston disposed to reciprocate therein, a rotary pump shaft having a cam surface thereon with its axis extending transversely to the cylinder, a. transverse roller having its axis parallel to the axis of said shaft,

REFERENCES CITED The following references are of le of this patent:

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